CouchbaseProperties should use the SPY LoggerFactory.

Before this change, these log messages were not properly
logged with respect to the configured logging endpoint.

Also, the informative log message has been degraded to
DEBUG, because it is not used that often and it generates
confusion.

Change-Id: Ibac70bf012be80439d4d2a4f894230d0fabadca2
Reviewed-on: http://review.couchbase.org/27597
Tested-by: Michael Nitschinger <michael.nitschinger@couchbase.com>
Reviewed-by: Matt Ingenthron <matt@couchbase.com>